1. Field of the Invention
The present invention relates to devices for forming elongate trenches such as are used for drainage purposes.
2. Description of the Prior Art
Previously known devices function in one of a number of ways.
A first type of device, broadly described as a back hoe, operates in the manner of a mechanical shovel and progressively excavates a trench by repeated scooping actions.
While such devices are suitable for forming a trench in confined areas and on uneven terrain, they include a considerable number of components which are exposed to a harsh operating environment. The resulting wear requires frequent replacement of the components.
Additionally, since their mode of operation requires the repetitive performance of a number of manually controlled, disjointed steps, the speed at which a back hoe can be operated is determined primarily by the skill of the operator.
A second type of device forms a trench by advancing a continuously cycling plurality of cutting and scooping elements through the ground. The elements may be mounted on a chain or wheel.
While this type of device is suitable for use by a relatively unskilled operator, it includes an inordinate number of moving parts which, like those of the back hoe, are subject to considerable wear. Additionally, these devices are generally inflexible with regard to the width of trench which they are capable of forming.
The complexity of such devices also precludes the inclusion of reasonably priced control systems, which would enable them to operate at an optimum speed having regard to the power of their driving motor and the power necessary to form the trench in any particular type of ground.
It is an object of the present invention to provide a trench forming device able to overcome or at least ameliorate the above mentioned shortcomings of the prior art.